The craniofacial region is a rare site for chondrosarcomas. These tumors may have osseous or extraosseous origin. Extraosseous chondrosarcomas have the same histological features as osseous chondrosarcomas. Chondrosarcomas usually present in the fifth to seventh decades of life, although several cases with younger age at presentation have been reported. They usually present as a painless mass that gradually progresses to various complaints, such visual impairment, nasal obstruction, and dental abnormalities. In this article, we present two cases of chondrosarcoma occurring at rather unusual locations. It is important to keep this rare malignancy in the list of differential diagnoses for a mass in the head and neck region, as these tumors may not always show the features typical of this malignancy.

Craniofacial chondrosarcomas are rare and may be osseous or extraosseous. They have the same age at onset as the typical chondrosarcoma, although young patient presentation is not unusual. They are usually symptomatic and the symptoms refer to the mass effect of the tumor and hence are varied. The most common sites of involvement are petroclival, spheno-occipital, and frontonasal synchondroses. Radiological diagnosis can be straightforward for lesions showing typical calcifications, however, tumors with atypical imaging appearances are not at all uncommon. It is important to keep this entity in the list of differential diagnoses for head and neck masses. Complete surgical resection is the treatment of choice.

Craniofacial chondrosarcomas are rare tumors accounting for less than 10% of malignancies in the head and neck region[1]. Chondrosarcomas more commonly involve the long bones, pelvis, and ribs. Craniofacial chondrosarcomas may arise from bone, cartilage, or soft-tissue structures, but have a predilection for the skull base which is related to their origin from the cartilaginous remnants of the petroclival, spheno-occipital, and frontonasal synchondroses[2,3]. However, they may arise from tissues that do not normally harbor cartilage. This represents the pluripotent differentiation of primitive mesenchymal cells[4]. They most commonly involve the mandible, maxilla, or cervical vertebrae[5]. Sinonasal chondrosarcomas account for a good number of cases of head and neck chondrosarcomas. Chondrosarcomas are slow-growing invasive tumors, and are usually high-grade[6].

Patients with sinonasal chondrosarcoma may present with chronic nasal discharge, nasal obstruction, epistaxis, headaches or proptosis. The diagnosis of head and neck chondrosarcomas is based on imaging and histopathology. Diagnosis on CT is based on the typical chondroid pattern of calcification. Chondrosarcomas are typically hypo- to isointense on T1-weighted MR images and markedly hyperintense on T2-weighted MR images. The T2 hyperintensity is related to the high water content of hyaline cartilage. They show a characteristic curvilinear septal enhancement on MR images which corresponds to fibrovascular bundles surrounding the cartilaginous nodules[7]. This septal enhancement pattern is helpful in the identification of low-grade chondrosarcoma. With high-grade lesions, this characteristic MR appearance is not seen. In addition, there is a relationship between the density of calcification in chondrosarcoma and the grade of malignancy. High-grade malignancies contain large areas of non-calcified tumor[8]. Another tumor of osseous origin found in the head and neck is osteosarcoma. The radiological differentiation between the two tumors can be challenging. In general, chondrosarcomas are less aggressive with erosion as the predominant behavior rather than frank destruction. Matrix mineralization is helpful when it is definitely osteoid, however, tumors may not be calcified or the matrix can show chondroid differentiation. Complete surgical excision is the only curative treatment for craniofacial chondrosarcoma. Radiotherapy and chemotherapy are not effective in these tumors.

In conclusion, chondrosarcomas should be considered in the differential diagnosis of head and neck masses with or without the typical calcification pattern.